Weight and measurement of barnyard grass

In 22 1 year BC, Qin Shihuang unified the weights and measures. With the development of economy and social progress, the requirements for weighing instruments are getting higher and higher. In the early years of the Eastern Han Dynasty, the wooden pole scale came into being, which became the premise and foundation for future generations to create scales. China is the first civilized country in the world to implement legal measurement, and its ancient measurement accuracy, measurement unit and measurement management system are unparalleled. In the Tang and Song Dynasties, the development of weighing instruments in China became more and more mature, and the unit of measurement was changed from "two baht, labor and millet" to "two money, cents, cents and cents". At that time, Liu, an official in charge of royal tribute storage in Song Dynasty, first created and invented the first wooden scale in China from 1004 to 1007, in view of the fact that the measurement accuracy of ordinary wooden scales at that time could only be accurate to "money". According to the measurement, the rod weighs one yuan (3. 1.25g), is one foot and two inches (400mm) long, and thallium weighs six cents (1.875g). The first deduction (initial milli), the minimum quantity is five cents (1.5625g), and the final quantity (maximum weighing) is one and a half yuan (4.69g); The second button (in the United States), and the last amount is one dollar (3.125g); The third button (the last one is ten cents), and the final amount is five cents (1.5625g). Such weighing accuracy is rare in the history of the development of weighing instruments in the world. This scale is exquisite in design and reasonable in structure, and its dividing value (measuring accuracy) is one centimeter, which is equivalent to 3 1.25mg today.